基本上!我需要使用jtextfields更改最初设置为红色的消息的颜色,除了改变颜色的位之外,所有代码都已完成,因为我不知道如何引用消息。我知道它需要进入@overide动作执行位,但它说它不能识别什么消息'是的,我已经尝试过message.setForeground(new Color(a,b,c));但是,对于在这里做什么的任何帮助都会很棒,谢谢。
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class CE203_2016_Ex1 extends JFrame {
JTextField tred, tgreen, tblue;
public CE203_2016_Ex1() {
JPanel panel1 = new JPanel(); //creates panels for the boxes that will hold the rgb values
JPanel panel2 = new JPanel();
tred = new JTextField("Red", 10);
tgreen = new JTextField("Green", 10); //creates boxes for rgb values
tblue = new JTextField("Blue", 10);
panel1.add(tred);
panel1.add(tgreen); //adding jtextfields to panels
panel1.add(tblue);
add(panel1, BorderLayout.SOUTH); //adding panels to frame
add(panel2, BorderLayout.CENTER);
JLabel message = new JLabel("hello"); //text
message.setForeground(new Color(255, 0, 0)); //original text set to red
JButton goButton = new JButton("Change"); //adds button to change colour
panel1.add(goButton);
panel2.add(message);
goButton.addActionListener(new ButtonHandler(this));
}
class ButtonHandler implements ActionListener {
private CE203_2016_Ex1 theApp;
public ButtonHandler(CE203_2016_Ex1 theApp) {
this.theApp = theApp;
}
@Override
public void actionPerformed(ActionEvent e) {
int a = Integer.parseInt(theApp.tred.getText());
int b = Integer.parseInt(theApp.tgreen.getText());
int c = Integer.parseInt(theApp.tblue.getText());
}
}
public static void main(String[] args) {
JFrame app = new CE203_2016_Ex1();
app.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
app.setSize(700, 700);
app.setVisible(true);
}
}
答案 0 :(得分:0)
您需要在应用中公开消息标签。这意味着您必须将JLabel消息作为应用程序的一个字段,然后添加一个getter来检索它。这样,任何有权访问您应用的内容都可以访问消息标签。
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class CE203_2016_Ex1 extends JFrame {
JTextField tred, tgreen, tblue;
JLabel message;
public CE203_2016_Ex1() {
JPanel panel1 = new JPanel(); //creates panels for the boxes that will hold the rgb values
JPanel panel2 = new JPanel();
tred = new JTextField("Red", 10);
tgreen = new JTextField("Green", 10); //creates boxes for rgb values
tblue = new JTextField("Blue", 10);
panel1.add(tred);
panel1.add(tgreen); //adding jtextfields to panels
panel1.add(tblue);
add(panel1, BorderLayout.SOUTH); //adding panels to frame
add(panel2, BorderLayout.CENTER);
message = new JLabel("hello"); //text
message.setForeground(new Color(255, 0, 0)); //original text set to red
JButton goButton = new JButton("Change"); //adds button to change colour
panel1.add(goButton);
panel2.add(message);
goButton.addActionListener(new ButtonHandler(this));
}
public JLabel getMessageLabel() {
return message;
}
class ButtonHandler implements ActionListener {
private CE203_2016_Ex1 theApp;
public ButtonHandler(CE203_2016_Ex1 theApp) {
this.theApp = theApp;
}
@Override
public void actionPerformed(ActionEvent e) {
int a = Integer.parseInt(theApp.tred.getText());
int b = Integer.parseInt(theApp.tgreen.getText());
int c = Integer.parseInt(theApp.tblue.getText());
theApp.getMesssageLabel().setForground(new Color(a, b, c));
}
}
public static void main(String[] args) {
JFrame app = new CE203_2016_Ex1();
app.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
app.setSize(700, 700);
app.setVisible(true);
}
}
重要的部分是:
JTextField tred, tgreen, tblue;
// Added field message for later use
JLabel message;
public CE203_2016_Ex1() {
// Enables you to get the message label from your app later on
public JLabel getMessageLabel() {
return message;
}
class ButtonHandler implements ActionListener {
int c = Integer.parseInt(theApp.tblue.getText());
// Gets the message label from your App and sets its foreground color
theApp.getMesssageLabel().setForground(new Color(a, b, c));
答案 1 :(得分:0)
您尝试从scope外部访问变量message
,因为您在构造函数中声明了JLabel,它只能由构造函数访问。所以你想在构造函数之外声明JLabel和JTextFields一样,我也建议为它申请private
。